Conventionally, in order to move an object in three or more degrees of freedom, it was necessary to employ at least three individual linear and/or rotary motors, each driving a single axis stage with the stages cascaded in series with each other. This required a number of appliances with a plurality of bearings supporting large masses which move in different directions. Each bearing having unwanted compliances. This resulted in resonances, friction, backlash and inaccuracy of movement. The lowest mode resonance frequency tended to be much slower than desirable, making high accuracy servo control difficult.
Accordingly, it is a primary object of the present invention to provide a new and improved alignment device, which will become apparent as the description proceeds.